1. Field of the Invention
The present invention relates to a treatment tool for endoscope that is used by being endoscopically inserted into a body cavity.
2. Description of Related Art
In the related art, a forceps having a pair of forceps members supported so as to be relatively rotatable to each other via a rotation shaft is known as a treatment tool for endoscope (hereinafter, simply referred to as a “treatment tool”) which has a flexible sheath and is used by being endoscopically inserted into a body cavity.
The pair of forceps members is connected to an operation section of a hand side by an operation wire. The pair of forceps members has a configuration that is relatively rotated around the rotation shaft, and is opened and closed, by the operation wire being advanced and retreated in an axial direction via the operation section.
In such a forceps, if the operation wire is continuously retreated even after the pair of forceps members is closed, a large amount of force is acted by the forceps members. For this reason, when the operation wire is further retreated in a state in which a tissue or the like is grasped by the forceps members, the force grasping the tissue becomes excessively large, and thus a burden is applied to the grasped tissue.
Japanese Unexamined Patent Application, First Publication No. H10-290803 suggests a treatment tool including display means which detects and displays an amount of force acted on a treatment section such as the forceps member accompanied by the operation of an operation slider for advancing and retreating the operation wire advanced and retreat using an amount of deflection of an elastic body. An operator is able to adjust the amount of force acted on the treatment section by detecting the amount of force acted on the treatment section using the display means and adjusting an amount of operation of the operation slider.
Most of the treatment tools are inserted through a channel of the endoscope, and are inserted into a body cavity. However, the endoscope can easily move erratically within a body, and in that case, the sheath inserted through the channel also expands and contracts along with the erratic movement of the endoscope. When the sheath expands and contracts, a relationship between the amount of operation of the operation section and the amount of force acted on the treatment section is changed.